Control method of heating device

ABSTRACT

The present disclosure discloses a control method of a heating device, which relates to a technical field of heating technique, the heating device comprising: a first water storage unit provided with a first heating mechanism; a second water storage unit communicated with the first water storage unit and provided with a second heating mechanism; and a first temperature detection device configured to measure a temperature of the second water storage unit.

TECHNICAL FIELD

The present disclosure relates to a technical field of heating technique and particularly to a control method of a heating device.

BACKGROUND ART

In order to reduce a thickness of an electric water heater in a direction perpendicular to a wall surface, a double-tank electric water heater appears in the market, which has a first tank and a second tank which are disposed in a vertical direction and communicated with each other. During use, if water is supplied to the outside through the first tank, the second tank is refilled with water, so that hot water in the second tank can be refilled into the first tank.

In this way, the influence of cold water refilled into the second tank on hot water output to the outside by the first tank can be reduced. However, there is a problem that a heat exchange between the first tank and the second tank is poor, and a water temperature stratification between the first tank and the second tank is serious. When the electric water heater supplies water to a user to a certain extent, a temperature of hot water output by the electric water heater drops rapidly and cannot reach a temperature required by the user, which causes a problem that a total amount of hot water supplied to the user at the temperature required by the user is not enough. Therefore, there is an urgent need for a control method of a heating device, which can more reasonably control heating timings and power distributions of heating mechanisms in the first tank and in the second tank, so that the first tank can supply more hot water at the temperature required by the user.

SUMMARY OF THE DISCLOSURE

In order to overcome the above defects of the prior art, a technical problem to be solved by the embodiments of the present disclosure is to provide a control method of a heating device, which can optimize heating power distributions of a first heating mechanism and a second heating mechanism, so as to further increase a water discharge amount at a temperature required by a user.

The specific technical solutions of the embodiments of the present disclosure are as follows: A control method of a heating device, the heating device comprising: a first water storage unit provided with a first heating mechanism; a second water storage unit communicated with the first water storage unit and disposed downstream of the first water storage unit, the second water storage unit being provided with a second heating mechanism; a water inlet pipe communicated with the first water storage unit; a water outlet pipe communicated with the second water storage unit; and a first temperature detection device configured to measure a temperature of the second water storage unit;

-   -   the control method comprises:     -   when the temperature detected by the first temperature detection         device is less than or equal to a first preset value,         controlling the first heating mechanism to heat, while the         second heating mechanism heating in a first preset power; and     -   when the temperature detected by the first temperature detection         device is less than or equal to a second preset value that is         less than the first preset value, controlling the second heating         mechanism to heat in a second preset power that is greater than         the first preset power.

Preferably, the second water storage unit is located above the first water storage unit.

Preferably, a lower portion of the second water storage unit is communicated with an upper end of the first water storage unit, and the first temperature detection device is configured to measure a temperature of the lower portion or the middle portion of the second water storage unit.

Preferably, when the temperature detected by the first temperature detection device is less than or equal to the first preset value, controlling the first heating mechanism to heat in a third preset power, and when the temperature detected by the first temperature detection device is less than or equal to the second preset value, controlling the first heating mechanism to stop heating.

Preferably, the second preset power is less than or equal to a maximum rated heating power of the heating device.

Preferably, the first heating mechanism comprises a first heating member, and the first heating mechanism heats in the third preset power when the first heating member heats.

Preferably, the second heating mechanism comprises a second heating member and a third heating member;

-   -   when the second heating member heats while the third heating         member does not heat, the second heating mechanism heats in the         first preset power; and     -   when the second heating member and the third heating member         simultaneously heat, the second heating mechanism heats in the         second preset power.

Preferably, the second heating mechanism comprises a second heating member which is a variable power heating member; when the temperature detected by the first temperature detection device is less than or equal to the first preset value, the second heating member can heat in the first preset power; and when the temperature detected by the first temperature detection device is less than or equal to the second preset value, the second heating member can heat in the second preset power.

Preferably, the control method further comprises:

-   -   obtaining a user set temperature value; and     -   obtaining the first preset value based on the user set         temperature value, the first preset value being in a positive         correlation relationship with the user set temperature value.

Preferably, the heating device further comprises: a second temperature detection device configured to measure a temperature of the first water storage unit;

-   -   the control method further comprises:     -   obtaining a user set temperature value; and     -   obtaining the second preset value based on the user set         temperature value and a change rate of the temperature detected         by the second temperature detection device.

Preferably, the second preset value is in a positive correlation relationship with the change rate of the temperature detected by the second temperature detection device.

Preferably, the second preset value is in a positive correlation relationship with the user set temperature value.

Preferably, when the temperature detected by the first temperature detection device reaches a third preset value, the second preset value is obtained based on the user set temperature value and the change rate of the temperature detected by the second temperature detection device, the third preset value being greater than the first preset value and less than the user set temperature value.

Preferably, the first temperature detection device is configured to measure a temperature of a lower portion of the second water storage unit, the lower portion of the second water storage unit being communicated with an upper portion of the first water storage unit;

-   -   the heating device further comprises a third temperature         detection device configured to measure a temperature of an upper         portion of the second water storage unit;     -   when the temperature detected by the third temperature detection         device reaches a third preset value, the second preset value is         obtained based on the user set temperature value and the change         rate of the temperature detected by the second temperature         detection device, the third preset value being greater than the         first preset value and less than the user set temperature value.

Preferably, when the temperature detected by the second temperature detection device is within a first range, the second preset value is obtained by subtracting a first preset parameter from the user set temperature value; and

-   -   when the temperature detected by the second temperature         detection device is within a second range, the second preset         value is obtained by subtracting a second preset parameter from         the user set temperature value, a temperature value within the         second range being less than a temperature value within the         first range, the first preset parameter being greater than the         second preset parameter, and the first preset parameter and the         second preset parameter being positive values.

Preferably, when the temperature detected by the second temperature detection device is within a third range, the second preset value is obtained by subtracting a third preset parameter from the user set temperature value; a temperature value within the third range is less than the temperature value within the second range, the second preset parameter is greater than the third preset parameter, and the third preset parameter is a positive value; and an intermediate value of each of the first range, the second range and the third range is in a linear relationship with the corresponding preset parameter.

Preferably, the water inlet pipe is communicated with a lower portion of the first water storage unit, and the second temperature detection device is configured to measure a temperature of the lower portion or the middle portion of the first water storage unit.

Preferably, the heating device further comprises a third temperature detection device configured to measure a temperature of an upper portion of the second water storage unit; the first temperature detection device is configured to measure a temperature of the lower portion or the middle portion of the second water storage unit, and the lower portion of the second water storage unit is communicated with an upper portion of the first water storage unit;

-   -   the control method further comprises:     -   obtaining a user set temperature value;     -   when the temperature detected by the first temperature detection         device is less than a maximum safe heatable temperature, the         temperature detected by the third temperature detection device         reaches a sum of the user set temperature value and a fifth         preset parameter, and when a temperature of the first water         storage unit does not reach the user set temperature value, the         first heating mechanism is controlled for heating, while the         second heating mechanism stops heating;     -   when the temperature detected by the first temperature detection         device is greater than or equal to the maximum safe heatable         temperature, the temperature detected by the third temperature         detection device reaches the user set temperature value, and         when the temperature of the first water storage unit does not         reach the user set temperature value, the first heating         mechanism is controlled for heating, while the second heating         mechanism stops heating.

Preferably, the heating device further comprises a third temperature detection device configured to measure a temperature of an upper portion of the second water storage unit; the first temperature detection device is configured to measure a temperature of the lower portion or the middle portion of the second water storage unit, and the lower portion of the second water storage unit is communicated with an upper portion of the first water storage unit;

-   -   the control method further comprises:     -   when a difference between the temperature detected by the third         temperature detection device and the temperature detected by the         first temperature detection device exceeds a fourth preset         parameter, controlling the second heating mechanism to heat in         the second preset power.

Preferably, the heating device further comprises a second temperature detection device configured to measure a temperature of the first water storage unit;

-   -   the control method further comprises:     -   obtaining a user set temperature value; and     -   when the temperature detected by the second temperature         detection device is less than the user set temperature value,         controlling the first heating mechanism to heat in a third         preset power.

The technical solutions of the present disclosure have the significant advantageous effects as follows:

According to the control method of the heating device in the present disclosure, when the first temperature detection device measuring the temperature of the second water storage unit measures that the temperature in the second water storage unit is less than or equal to the first preset value, i.e., when the water temperature in the second water storage unit decreases slightly, the first water storage unit is heated by the first heating mechanism, and the second water storage unit is heated by the second heating mechanism. At this time, the heating requirement of the second water storage unit can be met just by the second heating mechanism. As a result, the second water storage unit can continue outputting hot water at the temperature required by the user, and the remaining heating power of the heating device can be distributed to the first heating mechanism to heat the first water storage unit, so that the temperature of the water flowing from the first water storage unit into the second water storage unit can increase as much as possible. When the first temperature detection device measuring the temperature of the second water storage unit measures that the temperature in the second water storage unit is less than or equal to the second preset value, i.e., when the water temperature in the second water storage unit decreases more, the second heating mechanism is controlled for heating with greater power than before, so as to ensure that the second water storage unit can continue outputting hot water at the temperature required by the user for a longer time as much as possible, thereby further increasing the water discharge amount at the temperature required by the user.

With reference to the following descriptions and drawings, the particular embodiments of the present disclosure will be disclosed in detail to indicate the ways in which the principle of the present disclosure can be adopted. It should be understood that the scope of the embodiments of the present disclosure are not limited thereto. The embodiments of the present disclosure include many changes, modifications and equivalents within the spirit and clauses of the appended claims. The features described and/or illustrated with respect to one embodiment may be used in one or more other embodiments in the same or similar way, may be combined with the features in other embodiments, or may take place of those features.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described here are for explanatory purposes only and are not intended to limit the scope of the present disclosure in any way. In addition, the shapes and proportional sizes of the components in the drawings are just schematic to help the understanding of the present disclosure, rather than specifically limiting the shapes and proportional sizes of the components of the present disclosure. Under the teaching of the present disclosure, a person skilled in the art can select various possible shapes and proportional sizes according to specific conditions to carry out the present disclosure.

FIG. 1 is a flow chart of steps of a control method of a heating device in an embodiment of the present disclosure:

FIG. 2 is a schematic diagram of a structure of a heating device in an embodiment of the present disclosure.

REFERENCE SIGNS IN THE ABOVE DRAWINGS

-   -   1: first water storage unit;     -   2: second water storage unit;     -   3: first heating mechanism;     -   31: first heating member;     -   4: second heating mechanism;     -   41: second heating member;     -   42: third heating member;     -   5: water inlet pipe;     -   6: water outlet pipe;     -   7: first temperature detection device;     -   8: second temperature detection device;     -   9: third temperature detection device;     -   10: fourth temperature detection device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The details of the present disclosure can be more clearly understood in conjunction with the drawings and the description of specific embodiments of the present disclosure. However, the specific embodiments of the present disclosure described here are only for the purpose of explaining the present disclosure, and should not be construed as limitations to the present disclosure in any way. Under the teaching of the present disclosure, a skilled person can conceive any possible variations based on the present disclosure, which should be regarded as falling within the scope of the present disclosure. It should be noted that when an element is referred to as being ‘disposed’ on another element, it may be directly on another element or there may be an intermediate element. When an element is deemed as being ‘connected’ to another element, it may be directly connected to another element or there may be an intermediate element. The term ‘mounting’ or ‘connection’, etc. should be understood broadly, e.g., it may be a mechanical connection or an electrical connection, or a communication between interiors of two elements; and it may be a direct connection or an indirect connection through an intermediate medium. A person of ordinary skills in the art can understand the meaning thereof according to specific situations. As used herein, the terms ‘vertical’, ‘horizontal’, ‘upper’, ‘lower’, ‘left’, ‘right’ and similar expressions are for illustrative purposes only, rather than indicating unique embodiments.

Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by a person skilled in the technical field of the present disclosure. The terms used herein in the specification of the present disclosure are only for the purpose of describing the specific embodiments and are not intended to limit the present disclosure. As used herein, the term ‘and/or’ includes any and all combinations of one or more associated listed items.

In order to optimize a heating power distribution between a first heating mechanism and a second heating mechanism, and further increase a water discharge amount at a temperature required by a user, the present disclosure proposes a control method of a heating device. FIG. 1 is a flow chart of steps of a control method of a heating device in an embodiment of the present disclosure, and FIG. 2 is a schematic diagram of a structure of a heating device in an embodiment of the present disclosure. As illustrated in FIGS. 1 and 2 , the heating device comprises: a first water storage unit 1 provided with a first heating mechanism 3; a second water storage unit 2 communicated with the first water storage unit 1 and disposed downstream of the first water storage unit 1, the second water storage unit 2 being provided with a second heating mechanism 4; a water inlet pipe 5 communicated with the first water storage unit 1; a water outlet pipe 6 communicated with the second water storage unit 2; and a first temperature detection device 7 configured to measure a temperature of the second water storage unit 2. The control method may comprise: when the temperature detected by the first temperature detection device 7 is less than or equal to a first preset value, controlling the first heating mechanism 3 to heat, while the second heating mechanism 4 heating in a first preset power; and when the temperature detected by the first temperature detection device 7 is less than or equal to a second preset value that is less than the first preset value, controlling the second heating mechanism 4 to heat in a second preset power that is greater than the first preset power.

According to the control method of the heating device in the present disclosure, when the first temperature detection device 7 measuring the temperature of the second water storage unit 2 measures that the temperature in the second water storage unit 2 is less than or equal to the first preset value, i.e., when the water temperature in the second water storage unit 2 decreases slightly, the first water storage unit 1 is heated by the first heating mechanism 3, and the second water storage unit 2 is heated by the second heating mechanism 4. At this time, the heating requirement of the second water storage unit 2 can be met just by the second heating mechanism 4. As a result, the second water storage unit 2 can continue outputting hot water at the temperature required by the user, and the remaining heating power of the heating device can be distributed to the first heating mechanism 3 to heat the first water storage unit 1, so that the temperature of the water flowing from the first water storage unit 1 into the second water storage unit 2 can increase as much as possible. When the first temperature detection device 7 measuring the temperature of the second water storage unit 2 measures that the temperature in the second water storage unit 2 is less than or equal to the second preset value, i.e., when the water temperature in the second water storage unit 2 decreases more, the second heating mechanism 4 is controlled for heating with greater power than before, so as to ensure that the second water storage unit 2 can continue outputting hot water at the temperature required by the user for a longer time as much as possible, thereby further increasing the water discharge amount at the temperature required by the user.

In order for better understanding, the control method of the heating device in the present disclosure will be further explained and described below. As illustrated in FIG. 2 , the heating device may comprise: a first water storage unit 1 provided with a first heating mechanism 3; a second water storage unit 2 communicated with the first water storage unit 1 and disposed downstream of the first water storage unit 1, the second water storage unit 2 being provided with a second heating mechanism 4; a water inlet pipe 5 communicated with the first water storage unit 1; a water outlet pipe 6 communicated with the second water storage unit 2; a first temperature detection device 7 configured to measure a temperature of the second water storage unit 2; and a second temperature detection device 8 configured to measure a temperature of the first water storage unit 1. The first heating mechanism 3 is configured to heat water in the first water storage unit 1, and the second heating mechanism 4 is configured to heat water in the second water storage unit 2. Here, it should be noted that ‘the first heating mechanism 3 is configured to heat water in the first water storage unit 1’ may be understood as that most of heat generated by the first heating mechanism 3 is employed to heat the water in the first water storage unit 1. Of course, a small part of the heat generated by the first heating mechanism 3 can also heat the water in the second water storage unit 2, but the heating needs a water convection and a heat conduction, and the process is slow. The understanding of ‘the second heating mechanism 4 is configured to heat water in the second water storage unit 2’ is the same as above.

Water is fed into the heating device from the water inlet pipe 5, and influent cold water firstly reaches the first water storage unit 1. When the heating device supplies hot water to a user, the hot water in the second water storage unit 2 is output from the water outlet pipe 6. At this time, the second water storage unit 2 is refilled with the water in the first water storage unit 1, and the first water storage unit 1 is refilled with water from a water source.

The first temperature detection device 7 may be disposed at any position of the second water storage unit 2, provided that it can measure a general temperature in the second water storage unit 2. As practicable, as illustrated in FIG. 2 , when the second water storage unit 2 supplies hot water to the user, in order to detect at the first time that the water flowing from the first water storage unit 1 into the second water storage unit 2 causes a local temperature of the second water storage unit 2 to decrease, a lower portion of the second water storage unit 2 is communicated with an upper end of the first water storage unit 1, and the first temperature detection device 7 is configured to measure a temperature of a lower portion or a middle portion of the second water storage unit 2. In this way, the water flowing from the first water storage unit 1 into the second water storage unit 2 firstly reaches the lower portion of the second water storage unit 2. If a temperature of the water flowing from the first water storage unit 1 into the second water storage unit 2 is low, a temperature of hot water in the lower portion or the middle portion of the second water storage unit 2 will decrease, the first temperature detection device 7 can immediately detect a temperature change in the lower portion or the middle portion of the second water storage unit 2, and the heating device can perform a corresponding heating control logic step for reasonable heating.

As practicable, in the above embodiment, as illustrated in FIG. 2 , the second water storage unit 2 may be located above the first water storage unit 1. The water outlet pipe 6 is preferentially communicated with an upper portion of the second water storage unit 2, so that hot water in the upper portion of the second water storage unit 2 is preferentially output to the user. The water inlet pipe 5 may be preferentially communicated with a lower portion of the first water storage unit 1. Since the water delivered to the first water storage unit 1 by the water source through the water inlet pipe 5 is cold water with a higher density, it can stay at the lower portion of the first water storage unit 1 as much as possible after entering thereto, and achieve a relatively small degree of mixing with the hot water with a lower density in the upper portion of the first water storage unit 1, so that the water with a higher temperature in the upper portion of the first water storage unit 1 can be driven into the second water storage unit 2. Similarly, in the second water storage unit 2, the water delivered by the first water storage unit 1 to the second water storage unit 2 has a lower temperature and a higher density than the water in the second water storage unit 2, and it can stay in the lower portion of the second water storage unit 2 as much as possible after entering thereto, while achieving a relatively small degree of mixing with the hot water with a lower density in the upper portion of the second water storage unit 2, so that the water with a higher temperature in the upper portion of the second water storage unit 2 can be supplied to the user through the water outlet pipe 6. Generally, in the above way, the second water storage unit 2 in the heating device can supply a greater amount of hot water at the temperature required by the user.

The second temperature detection device 8 may be disposed at any position of the first water storage unit 1, provided that it can measure a general temperature in the first water storage unit 1. When the water inlet pipe 5 is communicated with the lower portion of the first water storage unit 1, as practicable, in order to detect at the first time that the water flowing into the first water storage unit 1 causes a local temperature of the first water storage unit 1 to decrease, the second temperature detection device 8 is configured to measure the temperature of the middle portion or the lower portion of the second water storage unit 2. In this way, the second temperature detection device 8 can immediately detect a temperature change in the middle portion or the lower portion of the first water storage unit 1, and the heating device can perform a corresponding heating control logic step for reasonable heating.

As practicable, in order to more accurately detect the temperature of the water supplied to the outside by the second water storage unit 2 through the water outlet pipe 6, the heating device may comprise: a third temperature detection device 9 configured to measure a temperature of the upper portion of the second water storage unit 2. As practicable, in order to more accurately detect the temperature of the water delivered by the first water storage unit 1 to the second water storage unit 2, the heating device may comprise: a fourth temperature detection device 10 configured to measure a temperature of the upper portion of the first water storage unit 1.

As illustrated in FIG. 1 , the control method of a heating device may comprise the steps of:

-   -   obtaining a user set temperature value. The user set temperature         value is a temperature value set by the user to which the water         heated by the heating device should reach. When the water heated         by the heating device reaches the user set temperature value,         the heating device stops heating the internal water, and         subsequently it only needs to heat and maintain the internal         water at the user set temperature value. The user may adjust the         user set temperature value of the heating device according to         his own need or different seasons.

After the user set temperature value is obtained, the first water storage unit 1 is heated by the first heating mechanism 3, and the second water storage unit 2 is heated by the second heating mechanism 4, so that the temperature in the whole heating device reaches the user set temperature value. At this stage, the heating device may not supply water to the outside. After the initial heating by the heating device is finished, the heating device may be in a heat preservation state to wait for the user to use the hot water.

When the user starts to use the hot water, the hot water in the second water storage unit 2 is output from the water outlet pipe 6. At this time, the water in the first water storage unit 1 is refilled into the second water storage unit 2, and the water source fills water into the first water storage unit 1. When the user just starts to use the hot water, the water refilled from the first water storage unit 1 into the second water storage unit 2 substantially approaches or reaches the user set temperature value, so the temperature in the second water storage unit 2 decreases slightly. On the other hand, the water refilled from the water source into the first water storage unit 1 is cold water, and the temperature in the first water storage unit 1 decreases rapidly. Therefore, when the temperature detected by the second temperature detection device 8 is less than the user set temperature value, the first heating mechanism 3 is controlled for heating in a third preset power, thereby heating the water in the first water storage unit 1, and slowing down its temperature decrease rate or slowly raising the temperature to the user set temperature value. The third preset power may be any power less than or equal to a maximum rated heating power of the first heating mechanism 3. Generally, in order for fastest heating, the third preset power is equal to the maximum rated heating power of the first heating mechanism 3.

As practicable, the first heating mechanism 3 may comprise a first heating member 31, and the first heating mechanism 3 heats in the third preset power when the first heating member 31 heats.

If the user continues using the hot water, the hot water in the second water storage unit 2 is output from the water outlet pipe 6, and the water source continuously fills cold water into the first water storage unit 1. The first heating mechanism 3 heating in the third preset power can no longer prevent the first water storage unit 1 from dropping to a low temperature. At this time, the water refilled by the first water storage unit 1 into the second water storage unit 2 is water with a low temperature, which causes the water temperature in the second water storage unit 2 to decrease at a relatively small extent. Therefore, after the user set temperature value is obtained, the heating device will obtain the first preset value based on the user set temperature value, and specifically, the first preset value may be in a positive correlation relationship with the user set temperature value. When the temperature detected by the first temperature detection device 7 is less than or equal to the first preset value, the first heating mechanism 3 is controlled for heating, while the second heating mechanism 4 heats in the first preset power. The user set temperature value is not a fixed value, instead, it can be changed by the user anytime. Thus, the first preset value obtained by the heating device increases as the user set temperature value increases, and vice versa. The first preset value may be or may be not in a linear relationship with the user set temperature value. Of course, the first preset value is certainly less than the user set temperature value. For example, the first preset value may be obtained by subtracting a positive number from the user set temperature value.

As practicable, the first heating mechanism 3 has been heating in the third preset power before, and at this time, the first heating mechanism 3 can be controlled to continue heating in the third preset power without changing the heating power thereof.

As the user continues using the hot water, the first water storage unit 1 fills a large amount of water with a low temperature into the second water storage unit 2, thereby causing the water temperature in the second water storage unit 2 to decrease at a relatively large extent. Therefore, when the first temperature detection device 7 detects that the temperature is less than or equal to the second preset value, the second preset value is less than the first preset value, and the heating device controls the second heating mechanism 4 to heat in a second preset power that is greater than the first preset power. That is, at this time, it is necessary to increase the heating power of the second heating mechanism 4 for the second water storage unit 2 as much as possible, so as to slow down the temperature decrease rate of the second water storage unit 2 as much as possible, and ensure that the hot water output by the second water storage unit 2 through the water outlet pipe 6 is as close as possible to the user set temperature value. As a result, it ensures that the second water storage unit 2 can continue outputting the hot water at the temperature required by the user for a longer time as much as possible, thereby further increasing the water discharge amount at the temperature required by the user. Here, the temperature required by the user may be understood as a temperature less than or equal to the user set temperature value. For example, the user set temperature value is 60 degrees and the temperature required by the user is 40 degrees. In a start stage, water consumed by the user is of 40 degrees obtained by mixing the hot water output by the second water storage unit 2 with cold water. As the temperature of the hot water output by the second water storage unit 2 decreases, the hot water output by the second water storage unit 2 is mixed with less cold water to reach 40 degrees. When the temperature of the hot water output by the second water storage unit 2 decreases to 40 degrees, the hot water output by the second water storage unit 2 no longer needs to be mixed with cold water. When the temperature of the hot water output by the second water storage unit 2 decreases below 40 degrees, it can be understood that the hot water output by the second water storage unit 2 does not meet the temperature required by the user.

In the above process, the second preset power is less than or equal to a maximum rated heating power of the heating device.

Practicably, when the temperature detected by the first temperature detection device 7 is less than or equal to the second preset value, the first heating mechanism 3 may be controlled to stop heating, so that the second preset power can be equal to the maximum rated heating power of the heating device in the above process.

In one practicable embodiment, the second heating mechanism 4 may comprise a second heating member 41 and a third heating member 42. When the second heating member 41 heats while the third heating member 42 does not heat, the second heating mechanism 4 heats in the first preset power. When the second heating member 41 and the third heating member 42 heat simultaneously, the second heating mechanism 4 heats in the second preset power.

In another practicable embodiment, the second heating mechanism 4 may comprise a second heating member 41 which is a variable power heating member. When the temperature detected by the first temperature detection device 7 is less than or equal to the first preset value, the second heating member 41 can heat in the first preset power; and when the temperature detected by the first temperature detection device 7 is less than or equal to the second preset value, the second heating member 41 can heat in the second preset power.

In the one practicable embodiment, since the maximum heating power of the second heating mechanism 4 can reach the maximum rated heating power of the heating device, both the first heating mechanism 3 and the second heating mechanism 4 in the heating device cannot heat in their own maximum heating power simultaneously, otherwise the maximum rated heating power of the heating device will be exceeded. Therefore, in different water consumption stages of the user, the heating device should reasonably distribute the heating power of the first heating mechanism 3 and the second heating mechanism 4, so as to ensure that the second water storage unit 2 can continuously output the hot water at the temperature required by the user for a longer time as much as possible, thereby further increasing the water discharge amount at the temperature required by the user.

Similarly, before the first temperature detection device 7 detects that the temperature is less than or equal to the second preset value, the heating device should obtain the second preset value in advance. Therefore, after the user set temperature value is obtained and the user starts to use the hot water so that the temperature detected by the second temperature detection device 8 is changed, the heating device should obtain the second preset value based on the user set temperature value and a change rate of the temperature detected by the second temperature detection device 8. Since the user set temperature value is not a fixed value, it can be changed anytime. In addition, a flow rate of cold water refilled into the first water storage unit 1 is varied since the second water storage unit 2 delivers hot water to the outside at a different flow rate each time, and the cold water refilled into the first water storage unit 1 has different temperatures due to seasonal differences, so the change rate of the temperature detected by the second temperature detection device 8 may be also different. Therefore, the second preset value should be in a positive correlation relationship with the change rate of the temperature detected by the second temperature detection device 8. At the same time, the second preset value should also be in a positive correlation relationship with the user set temperature value. That is, the second preset value obtained by the heating device increases as the user set temperature value increases, and vice versa. As the user set temperature value increases, the second heating mechanism 4 should heat in the second preset power as early as possible in order that the hot water output by the second water storage unit 2 is as close as possible to the user set temperature value, so the obtained second preset value increases. The second preset value obtained by the heating device increases as the change rate of the temperature detected by the second temperature detection device 8 increases, and vice versa. When the change rate of the temperature detected by the second temperature detection device 8 increases, it means that the water flow rate of the cold water refilled into the first water storage unit 1 increases or the temperature of the cold water decreases, and of course, both situations may occur. Therefore, it is necessary to heat in the second preset power by the second heating mechanism 4 as early as possible, and distribute more heating power to the second heating mechanism 4 as early as possible, so that the hot water output by the second water storage unit 2 is as close as possible to the user set temperature value, and the obtained second preset value increases. Otherwise, in a case where the water flow rate of the cold water refilled into the first water storage unit 1 increases or the temperature of the cold water decreases, if the distribution of the more heating power to the second heating mechanism 4 is late, there is not enough time to heat once the temperature in the second water storage unit 2 decreases by a relatively large amount, no matter how much heating power is distributed to the second heating mechanism 4, and the temperature of the hot water output by the second water storage unit 2 will decrease to a temperature not required by the user faster, which leads to a decrease of the water discharge amount output by the second water storage unit 2 at the temperature required by the user.

As practicable, when the temperature detected by the first temperature detection device 7 reaches the third preset value, the second preset value is obtained based on the user set temperature value and the change rate of the temperature detected by the second temperature detection device 8. The third preset value is great than that first preset value and less than the user set temperature value. That is, before the temperature in the second water storage unit 2 decreases to the first preset value, the heating device may calculate the specific value of the second preset value based on the user set temperature value and the change rate of the temperature detected by the second temperature detection device 8, so that the second preset value can be used in the later control logic steps. Of course, in other practicable embodiments, the second preset value may also be obtained based on the user set temperature value and the change rate of the temperature detected by the second temperature detection device 8 when the second water storage unit 2 outputs the hot water to the outside for a preset time length. The preset time length may be less than a time length in extreme cases, which is a time length by which the first temperature detection device 7 detects that the temperature is less than or equal to the second preset value, in a case where the second water storage unit 2 delivers the hot water to the outside at the maximum flow rate and the cold water refilled into the first water storage unit 1 is relatively cold. Since the flow rate of the hot water delivered by the second water storage unit 2 to the outside and the temperature of the cold water refilled into the first water storage unit 1 are known in the above extreme cases, the second preset value can be calculated artificially, so the time length by which the first temperature detection device 7 detects that the temperature is less than or equal to the second preset value can be obtained through experiments.

As practicable, when the second water storage unit 2 has temperatures at different positions detected by the first temperature detection device 7 and the third temperature detection device 9, i.e., when the first temperature detection device 7 measures a temperature of a middle portion or a lower portion of the second water storage unit 2 and the third temperature detection device 9 measures a temperature of a middle portion or an upper portion of the second water storage unit 2, through the temperature detected by the third temperature detection device 9, it is possible to determine when the heating device obtains the second preset value based on the user set temperature value and the change rate of the temperature detected by the second temperature detection device 8. Specifically, when the temperature detected by the third temperature detection device 9 reaches the third preset value, the second preset value is obtained based on the user set temperature value and the change rate of the temperature detected by the second temperature detection device 8. The third preset value is great than that first preset value and less than the user set temperature value. In this embodiment, the temperature detected by the third temperature detection device 9 is closest to the real temperature of the hot water output from the second water storage unit 2, which allows to most reliably and accurately determine when the heating device obtains the second preset value based on the user set temperature value and the change rate of the temperature detected by the second temperature detection device 8, thereby improving the accuracy of the obtained second preset value.

In a specific embodiment, based on the user set temperature value and the change rate of the temperature detected by the second temperature detection device 8, the second preset value may be obtained in the following ways: 1. When the temperature detected by the second temperature detection device 8 is within a first range, the second preset value is obtained by subtracting a first preset parameter from the user set temperature value. 2. When the temperature detected by the second temperature detection device 8 is within a second range, the second preset value is obtained by subtracting a second preset parameter from the user set temperature value. A temperature value within the second range is less than a temperature value within the first range, the first preset parameter is greater than the second preset parameter, and the first preset parameter and the second preset parameter are positive values. 3. The set ranges may be two or more, for example, when the temperature detected by the second temperature detection device 8 is within a third range, the second preset value is obtained by subtracting a third preset parameter from the user set temperature value; a temperature value within the third range is less than the temperature value within the second range, the second preset parameter is greater than the third preset parameter, and the third preset parameter is a positive value. The above ranges are successive as a whole to ensure that the temperature detected by the second temperature detection device 8 is certainly within a certain range. In the above ways, the aforementioned content can also be met, i.e., the second preset value is in a positive correlation relationship with the change rate of the temperature detected by the second temperature detection device 8, and the second preset value is in a positive correlation relationship with the user set temperature value. When the temperature detected by the first temperature detection device 7 reaches the third preset value, or when the temperature detected by the third temperature detection device 9 reaches the third preset value, the range becomes narrower as the change rate of the temperature detected by the second temperature detection device 8 increases, i.e., the temperature detected by the second temperature detection device 8 decreases. In this case, since the second preset value is obtained by subtracting a preset parameter from the user set temperature value, the preset parameter also decreases, so that the obtained second preset value increases.

In the above specific embodiment, since the change rate of the temperature detected by the second temperature detection device 8 is in a near-linear relationship with the change rate of the temperature detected by the first temperature detection device 7, an intermediate value of the range that temperatures detected by the second temperature detection device 8 within e is in a linear relationship with the second preset value corresponding to the range. Therefore, on the premise that the second preset value is obtained by subtracting a preset parameter from the user set temperature value, the intermediate value of the range that temperatures detected by the second temperature detection device 8 within is also in a linear relationship with the preset parameter corresponding to the range. For example, in a specific embodiment, when the temperatures detected by the second temperature detection device 8 are within different ranges and the intermediate values of the different ranges are in an arithmetic progression, the second preset values corresponding to the different ranges are also in an arithmetic progression, so that the first preset parameter, the second preset parameter and the third preset parameter are set in an arithmetic progression in turn.

As practicable, when the second water storage unit 2 has temperatures at different positions detected by the first temperature detection device 7 and the third temperature detection device 9, i.e., when the first temperature detection device 7 measures a temperature of a lower portion of the second water storage unit 2 and the third temperature detection device 9 measures a temperature of an upper portion of the second water storage unit 2, the second heating mechanism 4 may be controlled for heating in the second preset power if a difference between the temperature detected by the third temperature detection device 9 and the temperature detected by the first temperature detection device 7 exceeds a fourth preset parameter. Optionally, at the same time, the first heating mechanism 3 may be controlled to stop heating. If the second preset power is equal to the maximum rated heating power of the heating device, the first heating mechanism 3 must be controlled to stop heating. The fourth preset parameter may be an artificially set value, such as 1.5° C., 2° C. or 2.5° C., etc. In this way, the heating device can directly detect that the second water storage unit 2 delivers water to the outside at a large flow rate, i.e., the cold water from the water source is refilled into the first water storage unit 1 at a large flow rate. The user's consumption of the hot water at a large flow rate causes a larger temperature difference between the lower portion and the upper portion of the second water storage unit 2, and the temperature difference increases as the flow rate of the hot water consumed by the user rises. Therefore, by detecting the temperature difference between the lower portion and the upper portion of the second water storage unit 2, the heating device can determine the specific flow rate at which the hot water is consumed by the user. If the temperature detected by the first temperature detection device 7 is still greater than the second preset value, while the heating device has judged that the user is consuming the hot water at a large flow rate from the determination that a difference between the temperature detected by the third temperature detection device 9 and the temperature detected by the first temperature detection device 7 exceeds a fourth preset parameter, the heating device can control the second heating device 4 to heat in the second preset power as early as possible, slow down the temperature decrease rate of the second water storage unit 2 as much as possible, and ensure that the hot water output by the second water storage unit 2 through the water outlet pipe 6 is as close as possible to the user set temperature value. Thus, the second water storage unit 2 can continuously output the hot water at the temperature required by the user for a longer time, thereby further increasing the water discharge amount at the temperature required by the user.

In the heating device of the present application, the second preset value is not a fixed value, and it is determined each time according to the actual consumption of the hot water used by the user and the temperature of the cold water refilled into the first water storage unit 1, i.e., the second preset value is obtained based on the user set temperature value and the change rate of the temperature detected by the second temperature detection device 8. Further, in this way, without providing a flow rate detection device to detect a water filling flow rate of the first water storage unit 1, or providing an additional temperature detection device to detect the temperature of the cold water input into the first water storage unit 1 through the water inlet pipe 5, the heating device can judge the flow rate of the cold water input into the first water storage unit 1 through the water inlet pipe 5 per unit time, so as to calculate a reasonable second preset value. In the present application, the way of obtaining the second preset value greatly reduces the number of the components and the cost of the heating device.

After the first temperature detection device 7 detects that the temperature is less than or equal to the second preset value and the second heating mechanism 4 is controlled for heating in the second preset power, when it is detected that the temperature of the second water storage unit 2 reaches the user set temperature value while the temperature of the first water storage unit 1 does not reach the user set temperature value, the first heating mechanism 3 is controlled for heating while the second heating mechanism 4 stops heating. This can happen in the following scenario: after the first temperature detection device 7 detects that the temperature is less than or equal to the second preset value and the second heating mechanism 4 is controlled for heating in the second preset power, the flow rate of the hot water delivered by the second water storage unit 2 to the outside decreases to a low value. At this time, the temperature in the second water storage unit 2 may be increased by heating by the second heating mechanism 4 in the second preset power, and after a period of time, the temperature of the second water storage unit 2 will rise to the user set temperature value again. In order to prevent the temperature of the second water storage unit 2 from exceeding the user set temperature value, it is necessary to control the first heating mechanism 3 for heating while the second heating mechanism 4 to stop heating, so that the first water storage unit 1 can also be heated to the user set temperature value, thereby preparing for the subsequent delivery of the hot water at a large flow rate from the second water storage unit 2, and further increasing the water discharge amount of the heating device at the temperature required by the user as much as possible.

In the above process, it should be noted that as practicable, in the embodiment where the second water storage unit 2 has temperatures at different positions detected by the first temperature detection device 7 and the third temperature detection device 9, i.e., the first temperature detection device 7 measures a temperature of a lower portion of the second water storage unit 2 and the third temperature detection device 9 measures a temperature of an upper portion of the second water storage unit 2, when the heating device is an electric water heater, in order to protect the water storage device in the electric water heater and avoid dangers, a maximum safe heatable temperature of the electric water heater can only be set to 70° C. in the industry, and the electric water heater will stop heating after the actual temperature reaches 70° C. or slightly exceeds 70° C. to 71° C. or 72C. Therefore, when the temperature detected by the first temperature detection device 7 is less than the maximum safe heatable temperature, the temperature detected by the third temperature detection device 9 reaches the user set temperature value plus a fifth preset parameter, and the temperature of the first water storage unit 1 does not reach the user set temperature value, the first heating mechanism 3 is controlled for heating, while the second heating mechanism 4 stops heating. The fifth preset parameter may be an artificially set deviation value, such as a number greater than 0, generally less than 3, and for example an intermediate value of 2 may be taken. When the temperature detected by the first temperature detection device 7 is greater than or equal to the maximum safe heatable temperature, the temperature detected by the third temperature detection device 9 reaches the user set temperature value, and the temperature of the first water storage unit 1 does not reach the user set temperature value, the first heating mechanism 3 is controlled for heating, while the second heating mechanism 4 stops heating. In this embodiment, the temperature of the upper middle portion of the second water storage unit 2 is generally greater than or equal to the temperature of the lower portion in the heating process of the heating device or the process of outputting the hot water to the outside. Therefore, when the temperature detected by the first temperature detection device 7 is greater than or equal to the maximum safe heatable temperature, the temperature detected by the third temperature detection device 9 is generally greater than or equal to the temperature detected by the first temperature detection device 7, i.e., greater than or equal to 70° C., which certainly reaches the user set temperature value, and the temperature after a sufficient mixing in the whole second water storage unit 2 certainly meets the user set temperature value. When the temperature detected by the first temperature detection device 7 is less than the maximum safe heatable temperature, the temperature detected by the first temperature detection device 7 is probably less than the temperature detected by the third temperature detection device 9. Only when the second heating mechanism 4 is controlled to stop heating after the temperature detected by the third temperature detection device 9 reaches the user set temperature value plus the fifth preset parameter, the temperature of the second water storage unit 2 after the water of upper portion and the lower portion of the second water storage unit 2 are fully mixed will approach and reach the user set temperature value. If a reasonable fifth preset parameter is not set and the second heating mechanism 4 is controlled to stop heating just by measuring the temperature of the upper portion or the lower portion of the second water storage unit 2, the temperature of the second water storage unit 2 after the water of the upper portion and the lower portion of the second water storage unit 2 are fully mixed will either not reach the user set temperature value at all or exceed the user set temperature value by a lot, which will lead to the problem of poor accuracy.

All articles and references disclosed, including patent applications and publications, are incorporated herein by reference for all purposes. The phrase ‘substantially composed of . . . ’ describing a combination should include the determined elements, compositions, components or steps, and any other element, composition, component, or step which substantively does not affect the basic novel features of the combination. When the term ‘comprise’ or ‘include’ is used to describe the combination of elements, compositions, components or steps herein, embodiments substantially consisting of the elements, compositions, components or steps are also contemplated. Herein the term ‘may’ is used to indicate that any described attribute covered by ‘may’ is optional. Multiple elements, compositions, components, or steps can be provided by a single integrated element, composition, component or step. Alternatively, a single integrated element, composition, component or step may be divided into multiple separate elements, compositions, components or steps. The disclosure ‘a/an’ or ‘one’ used to describe the elements, compositions, components or steps is not intended to exclude other elements, compositions, components or steps.

Each embodiment in the specification is described in a progressive manner. Each embodiment lays an emphasis on its difference from other embodiments, and the same or similar parts of the embodiments can refer to each other. The above embodiments are only used to describe the technical ideas and characteristics of the present disclosure, and the purpose is to allow a person skilled in the art to understand the contents of the present disclosure and implement them accordingly, rather than limiting the protection scope of the present disclosure. Any equivalent change or modification made according to the spirit essence of the present disclosure shall fall within the protection scope of the present disclosure. 

1. A control method of a heating device, the heating device comprising: a first water storage unit provided with a first heating mechanism; a second water storage unit communicated with the first water storage unit and disposed downstream of the first water storage unit, the second water storage unit being provided with a second heating mechanism; a water inlet pipe communicated with the first water storage unit; a water outlet pipe communicated with the second water storage unit; and a first temperature detection device configured to measure a temperature of the second water storage unit; the control method comprises: when the temperature detected by the first temperature detection device is less than or equal to a first preset value, controlling the first heating mechanism to heat, while the second heating mechanism heating in a first preset power; and when the temperature detected by the first temperature detection device is less than or equal to a second preset value that is less than the first preset value, controlling the second heating mechanism to heat in a second preset power that is greater than the first preset power.
 2. The control method of the heating device according to claim 1, wherein the second water storage unit is located above the first water storage unit.
 3. The control method of the heating device according to claim 2, wherein a lower portion of the second water storage unit is communicated with an upper end of the first water storage unit, and the first temperature detection device is configured to measure a temperature of the lower portion or the middle portion of the second water storage unit.
 4. The control method of the heating device according to claim 1, wherein when the temperature detected by the first temperature detection device is less than or equal to the first preset value, controlling the first heating mechanism to heat in a third preset power, and when the temperature detected by the first temperature detection device is less than or equal to the second preset value, controlling the first heating mechanism to stop heating.
 5. The control method of the heating device according to claim 4, wherein the second preset power is less than or equal to a maximum rated heating power of the heating device.
 6. The control method of the heating device according to claim 4, wherein the first heating mechanism comprises a first heating member, and the first heating mechanism heats in the third preset power when the first heating member heats.
 7. The control method of the heating device according to claim 1, wherein the second heating mechanism comprises a second heating member and a third heating member; when the second heating member heats while the third heating member does not heat, the second heating mechanism heats in the first preset power; and when the second heating member and the third heating member simultaneously heat, the second heating mechanism heats in the second preset power.
 8. The control method of the heating device according to claim 1, wherein the second heating mechanism comprises a second heating member which is a variable power heating member; when the temperature detected by the first temperature detection device is less than or equal to the first preset value, the second heating member can heat in the first preset power; and when the temperature detected by the first temperature detection device is less than or equal to the second preset value, the second heating member can heat in the second preset power.
 9. The control method of the heating device according to claim 1, wherein the control method further comprises: obtaining a user set temperature value; and obtaining the first preset value based on the user set temperature value, the first preset value being in a positive correlation relationship with the user set temperature value.
 10. The control method of the heating device according to claim 1, wherein the heating device further comprises: a second temperature detection device configured to measure a temperature of the first water storage unit; the control method further comprises: obtaining a user set temperature value; and obtaining the second preset value based on the user set temperature value and a change rate of the temperature detected by the second temperature detection device.
 11. The control method of the heating device according to claim 10, wherein the second preset value is in a positive correlation relationship with the change rate of the temperature detected by the second temperature detection device.
 12. The control method of the heating device according to claim 10, wherein the second preset value is in a positive correlation relationship with the user set temperature value.
 13. The control method of the heating device according to claim 10, wherein when the temperature detected by the first temperature detection device reaches a third preset value, the second preset value is obtained based on the user set temperature value and the change rate of the temperature detected by the second temperature detection device, the third preset value being greater than the first preset value and less than the user set temperature value.
 14. The control method of the heating device according to claim 10, wherein the first temperature detection device is configured to measure a temperature of a lower portion of the second water storage unit, the lower portion of the second water storage unit being communicated with an upper portion of the first water storage unit; the heating device further comprises a third temperature detection device configured to measure a temperature of an upper portion of the second water storage unit; when the temperature detected by the third temperature detection device reaches a third preset value, the second preset value is obtained based on the user set temperature value and the change rate of the temperature detected by the second temperature detection device, the third preset value being greater than the first preset value and less than the user set temperature value.
 15. The control method of the heating device according to claim 10, wherein when the temperature detected by the second temperature detection device is within a first range, the second preset value is obtained by subtracting a first preset parameter from the user set temperature value; and when the temperature detected by the second temperature detection device is within a second range, the second preset value is obtained by subtracting a second preset parameter from the user set temperature value, a temperature value within the second range being less than a temperature value within the first range, the first preset parameter being greater than the second preset parameter, and the first preset parameter and the second preset parameter being positive values.
 16. The control method of the heating device according to claim 15, wherein when the temperature detected by the second temperature detection device is within a third range, the second preset value is obtained by subtracting a third preset parameter from the user set temperature value; a temperature value within the third range is less than the temperature value within the second range, the second preset parameter is greater than the third preset parameter, and the third preset parameter is a positive value; and an intermediate value of each of the first range, the second range and the third range is in a linear relationship with the corresponding preset parameter.
 17. The control method of the heating device according to claim 10, wherein the water inlet pipe is communicated with a lower portion of the first water storage unit, and the second temperature detection device is configured to measure a temperature of the lower portion or the middle portion of the first water storage unit.
 18. The control method of the heating device according to claim 4, wherein the heating device further comprises a third temperature detection device configured to measure a temperature of an upper portion of the second water storage unit; the first temperature detection device is configured to measure a temperature of a lower portion of the second water storage unit, and the lower portion or the middle portion of the second water storage unit is communicated with an upper portion of the first water storage unit; the control method further comprises: obtaining a user set temperature value; when the temperature detected by the first temperature detection device is less than a maximum safe heatable temperature, the temperature detected by the third temperature detection device reaches a sum of the user set temperature value and a fifth preset parameter, and when a temperature of the first water storage unit does not reach the user set temperature value, the first heating mechanism is controlled for heating, while the second heating mechanism stops heating; when the temperature detected by the first temperature detection device is greater than or equal to the maximum safe heatable temperature, the temperature detected by the third temperature detection device reaches the user set temperature value, and when the temperature of the first water storage unit does not reach the user set temperature value, the first heating mechanism is controlled for heating, while the second heating mechanism stops heating.
 19. The control method of the heating device according to claim 1, wherein the heating device further comprises a third temperature detection device configured to measure a temperature of an upper portion of the second water storage unit; the first temperature detection device is configured to measure a temperature of the lower portion or the middle portion of the second water storage unit, and the lower portion of the second water storage unit is communicated with an upper portion of the first water storage unit; the control method further comprises: when a difference between the temperature detected by the third temperature detection device and the temperature detected by the first temperature detection device exceeds a fourth preset parameter, controlling the second heating mechanism to heat in the second preset power.
 20. The control method of the heating device according to claim 1, wherein the heating device further comprises a second temperature detection device configured to measure a temperature of the first water storage unit; the control method further comprises: obtaining a user set temperature value; and when the temperature detected by the second temperature detection device is less than the user set temperature value, controlling the first heating mechanism to heat in a third preset power. 